The accuracy of seismic estimates of dynamic strains: An evaluation using strainmeter and seismometer data from Piñon Flat observatory, California

摘要: Abstract The dynamic strains associated with seismic waves may play a significant role in earthquake triggering, hydrological and magmatic changes, damage, ground failure. We determine how accurately be estimated from seismometer data elastic-wave theory by comparing such measured on three-component long-base strainmeter system at Pinon Flat, California. quantify the uncertainties errors through cross-spectral analysis of three regional earthquakes (the M 0 = 4 × 10 17 N-m St. George, Utah; Little Skull Mountain, Nevada; 1 19 Northridge, California, events distances 470, 345, 206 km, respectively). Our indicates that most cases phase strain matches observed quite well (to within uncertainties, which are about ±0.1 to ±0.2 cycles). However, amplitudes often systematically off, levels exceeding (about 20%); one case, predicted nearly twice those observed. also observe ɛ φφ ( φ tangential direction), should zero theoretically; worst rms exceeds other nonzero components. These cannot caused deviations surface-wave propagation paths expected azimuth or departures plane-wave approximation. believe distortion field topography material heterogeneities give rise these complexities.